diff --git a/drm/DrmProperty.cpp b/drm/DrmProperty.cpp
index 76fb4f9..8dc62f6 100644
--- a/drm/DrmProperty.cpp
+++ b/drm/DrmProperty.cpp
@@ -150,10 +150,15 @@
     return false;
   }
 
+  if (!IsBitmask()) {
+    ALOGE("Property %s is not a bitmask property.", name_.c_str());
+    return false;
+  }
+
   mask = 0;
 
   for (const auto &it : enums_) {
-    mask |= it.value;
+    mask |= (1 << it.value);
   }
 
   return true;
diff --git a/drm/DrmProperty.h b/drm/DrmProperty.h
index 860f9ca..99bddb1 100644
--- a/drm/DrmProperty.h
+++ b/drm/DrmProperty.h
@@ -54,6 +54,10 @@
     return id_ != 0 && (flags_ & DRM_MODE_PROP_RANGE) != 0;
   }
 
+  bool IsBitmask() const {
+    return id_ != 0 && (flags_ & DRM_MODE_PROP_BITMASK) != 0;
+  }
+
   auto RangeMin() const -> std::tuple<int, uint64_t>;
   auto RangeMax() const -> std::tuple<int, uint64_t>;